Three raw waters of fundamentally different natural organic matter (NOM)
character were treated by magnetic resin using a bench-scale method designed to
mimic how the resin is used in continuous operation. Increasing water
hydrophobicity resulted in reduced dissolved organic carbon (DOC) removal with
removal of 56%, 33% and 25% for waters containing 21%, 50% and 75% hydrophobic
NOM, respectively. Study of consecutive resin uses showed that the NOM in the
hydrophobic water had high affinity for the resin shown by DOC removal of 65%
after the first use of the resin. This dropped to 25% DOC removal after 15
consecutive resin uses. For the more hydrophilic waters, NOM removal remained
consistent after each resin use. The hydrophobic sample contained higher MW NOM
that was capable of blocking resin sites that prevented continual adsorption of
organics on to the resin. The hydrophilic NOM containing a large proportion of
hydrophilic acids was consistently removed to around 60%. The water containing
algogenic-derived NOM was poorly removed by magnetic resin. Subsequent
coagulation showed higher removal with increasing hydrophobicity. (C) 2007
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